#define _CRT_SECURE_NO_WARNINGS
#define PI 3.1415926
#include <stdio.h>
#include <math.h>

double S(double r)
{
	double aear = PI * pow(r, 2);
	return aear;
}
int main() 
{
	S(1) > S(2) ? printf("%lf", S(1)) :printf("%lf", S(2));
	return 0;
} 